1. Field of the Invention
The present invention relates to a steerable catheter device, and more particularly to a device useful in minimally invasive surgery, urology, gynecology and hysteroscopy or the like.
2. Description of Related Art
One of the problems associated with procedures such as minimally invasive surgery is the lack of inexpensive small diameter instruments that can be steered into desired locations in the body of a patient. Most of the present available instruments are straight. Steerable instruments are also currently available. However, most of the steerable instruments presently available are complex and heavy. These instruments are generally limited to diameters of 3.6 mm or larger and require complex constructions to accomplish the desired results. At the present time there is no flexible instrument available which enables the instrument to be readily steered within the human body with a minimum of discomfort to the patient while at the same time being small, inexpensive and simple in construction.
Moreover, most presently available instruments require sterilization through the use of cold soak systemsxe2x80x94i.e. gluteraldehyde or sterris/sterrad systems. This poses a problem because there have been numerous cases of incomplete sterilization of steerable instruments.
Accordingly, there exists a need for an inexpensive, lightweight, simply constructed instrument that guides and/or steers other instruments. Furthermore, there needs to be a low cost single use instrument to preclude the potential for cross contamination.
In accordance with this need, the present invention is of lightweight inexpensively constructed steerable catheter device including a handle means which can be held like a pencil. The handle means provides greater sensitivity and tactile feel to the user than is possible with present day devices of this type. Greater sensitivity is provided by the reduction in weight on the handle. Alternatively, the handle means can be shaped as a pistol grip. When shaped as a pistol grip, the probe is constructed so that activation of the handle causes the motion of the probe to be advanced.
In either configuration the activation portion of the steerable catheter can be designed as a reusable piece, since the activation portion is more robust. In this case, the small diameter catheter would be disposable, and provide much simpler delivery to the patient. Reusing portions of the steerable catheter would also lower costs because less material is disposed of with each use.
The handle means supports an elongated outer sheath and an elongated catheter extends through the sheath. The catheter is movable lengthwise of the sheath and is rotatable with respect to the sheath. The outer end of the catheter comprises a memory tip which causes the tip to be disposed at a desired angle to the sheath when the tip is extended a certain distance from the sheath.
The sheath may be substantially rigid, or it may be formed of flexible material. In either case, the catheter is more flexible than the sheath. When the sheath is of flexible construction, complex shapes and bends can be created by rotating the catheter within the sheath. Moreover, with a flexible sheath, the invention may be used not only as a steering instrument but also as a dissection tool.
The instruments and catheters are passed down the lumen of the flexible sheath. Therefore, the inner catheter can be more flexible than would be normally deemed safe because inner catheter is able to secure and derive the wall thickness and strength from the sheath. This construction significantly reduces the potential for breakage.
The handle means includes a body portion which is connected to the sheath and a handle portion which is connected to the catheter. The handle portion is movable with respect to the body portion. These two portions have engageable shoulders formed thereon to limit movement in opposite directions of the catheter relative to the sheath. The sheath may be grasped in one hand of a user to hold the sheath and body portion in position while the other hand manipulates the handle portion to advance or retract the catheter with respect to the sheath and to additionally rotate the catheter with respect to the sheath.
In the pistol grip configuration, the handle is under a spring-loaded force to maintain a backpressure on the handle. The operation may therefore be accomplished in a one handed function. Squeezing the handle causes the insertion of the inner catheter within the outer sheath (as indicated above). A knurled knob on the rotatable portion of the instrument allows the user to adjust the position of the probe by extending a finger and dialing the appropriate position.
Once the tip of the catheter is properly positioned, a suitable medical device can be inserted and advanced through the catheter. For example, an endoscope may be advanced to view tissue more closely, or it can be withdrawn to provide a wider field of view.
The inner lumen can be multi lumen thereby allowing for more than one instrument or device to be inserted (up to the limits of device flexibility). For example, both a small diameter endoscope could be inserted in conjunction with another device; thus delivering both visualization and treatment modalities. Because of the lumens of the inner catheter are adjusted simultaneously (i.e. they are fixed in relative position), the user has the ability to easily move, visualize and deliver the treatment without the additional complication of relative spacexe2x80x94relative relationship to each instrument.
A first lock means is supported by the handle means for adjusting the force required to advance and retract the catheter, or to lock the catheter in place relative to the sheath. A second lock means is provided for locking a medical device in position within the catheter. This second lock means can also be adjusted to vary the force required to advance and retract the medical device, if so desired.
The catheter is spaced from the sheath to provide an annular channel there between. The outer end of the sheath has holes formed there through in communication with the annular channel. A fitting is supported by the handle means and has a bore therein in fluid communication with the annular channel. The fitting is also in fluid communication with an irrigation inflow and aspiration outflow tube to allow a constant interchange of fluids within a patient""s body cavity or organ to clear the surgical site of debris or blood. The holes in the outer end of the sheath allow irrigation media to be discharged therefrom evenly without a high pressure point. Alternatively, the irrigation system can be used in the delivery of a distension media, a contrast media, or any other desired media.
The relationship of irrigation and aspiration can be altered in that the aspiration can be from the outer tube with the irrigation from the inner tubexe2x80x94the application of the fenestrations on the outer tube preclude the adherence to the tissue wall via the suction creating a high vacuum point.
The steerable catheter of the present invention is inexpensive to manufacture, and its size as it relates to anatomical structures provides a device which is far more comfortable to the patient. When the medical device employed is an endoscope, smaller endoscopes may be interchanged for larger ones as the endoscopes are introduced into smaller diameter channels of the patient. Furthermore, since the endoscope used is a sealed instrument (and requires no working channels because the instrument in which it is inserted maintains the working channels) sterilization thereof is far more a complete and simpler to perform. The used outer sheaths and catheters are simply disposed of and replaced with new items, while the inner scope and other materials may (if applicable) be sterilized.
The system can be used in conjunction with vascular procedurexe2x80x94specially in those instances where there is the use of guidewires. Typically guidewires are used as a leading devicexe2x80x94introduced and passed into the area of the vasculature where the larger instrument could either not get to due to size, conformabilityxe2x80x94or other anatomical issues. To use a guidewire with the present invention, the guidewire is first introduced into the human vasculature. After the guidewire is in place in the body, the guidewire is introduced into the lumen of the instrumentxe2x80x94at the active tip. The guidewire is threaded through the catheter until the end of the guidewire exits the rear port of the instrument. The catheter is then introduced into the vasculature, and delivered to the appropriate surgical site by following the guidewire. Because the guidewire is smaller than the instrument, the use of the guidewire allows the instrument tip to reach the desired specific intervention site.
In another aspect of the current invention, the previously described system can be designed so that it mates with an ultrasonic energy source/system. In other words, the ultrasonic probe is introduced into the delivery catheter. In this case, the ultrasonic probe has a wide portion which is semi rigid. This wide portion mates with steerable catheter delivery section. The flexible thin portion of the probe resides within the flexible portion of the delivery system. In operation, the larger more rigid section of the probe does not exhibit vibration patterns. Therefore, the mating of the two surfaces is not problematic (which might be a problem if the large section vibrated). Furthermore, because of this characteristic, the two sections may be xe2x80x9chard matedxe2x80x9d together. In the area of the thin section of the ultrasonic probexe2x80x94it is smaller than the surrounding deflecting catheter and therefore is capable of vibrating in the transverse manner. One suitable ultrasonic probe is described in applicant""s co-pending application Ser. No. 09/618,352 which was filed on Jul. 19, 2000, and which is incorporated in its entirety herein.